1. Field of the Invention
The present invention relates to a map information providing system that provides a user with a map information with a proper reduced scale on the basis of a relationship between the present position of the user and a position of a target object. More in detail, the invention relates to a map information providing apparatus and method both of which can accomplish the above mentioned operation of the system.
2. Description of the Related Art
As means for providing a user with a positional information about a user""s destination, Japanese Patent Application Laid-open No. 11-230761 discloses a navigation system that can display a detailed positional information centering a destination established by the user. In the operation, when a destination is clearly designated by the user, this navigation system performs a so called xe2x80x9cdownloadxe2x80x9d operation to take in a map information of a narrow (or restricted) area arranging the designated destination as a map center. To the contrary, if the position of a user""s destination is vague, for example, a situation that a user""s destination is designated in the form of xe2x80x9cone destination or thereaboutsxe2x80x9d, then the systems loads a map information of a wide area including the destination.
Meanwhile, as to the situation that a user desires to acquire a detailed map information, there can be expected two cases as follows. That is, one case is a situation where the user possesses enough information to specify a destination clearly and therefore, the user wants to reach the destination smooth as possible. Another case is a situation that, for example, a user cannot identify the present position of a user""s vehicle since the user misses the user""s way and therefore, the user wants to reach a target object for the moment (e.g. interchange for free way) that enables the user to recognize the present position of the user""s vehicle.
The above mentioned navigation system disclosed in Japanese Patent Application Laid-open No. 11-230761 can cope with the former case, but the system cannot cope with the latter case. Because an indispensable information for the user in the latter case is not a map in the neighborhood of the user""s final destination but a map information illustrating the positional relationship between the user""s vehicle and the target object for the moment. To the contrary, since the above navigation system is constructed so as to provide the user with a map information about the user""s vehicle or the final destination, it is impossible to cope with such a user""s requirement.
In detail with the operation of the above navigation system, there is a possibility that the so loaded map information contains only the position of the user""s vehicle but the position of the target object, in other words, both of the positions are not displayed in one picture on a display unit simultaneously. In such a case, the user cannot grasp the positional relationship between the user""s vehicle and the target object for the moment (e.g. interchange for freeway) clearly although the user grasps an absolute position of the user""s vehicle on map. Then, the user has to again order the system to perform the download operation for taking in a map information with a larger scale.
Additionally, if the user""s vehicle is present on an urban street or the like despite that both of the user""s vehicle and the target object are displayed on the display unit simultaneously, then the user requires a more detailed map. Also in this case, the user has to again order the system to perform the download operation for taking in a map information with a smaller scale.
In the above way, if the map information is not provided with appropriate area and appropriate reduced scale, then a problem arises in that the user is burdened with superfluous time, excessive communication fee and manipulations.
Under the above mentioned circumstances, it is an object of the present invention to provide map information providing apparatus and method that calculate an appropriate reduced scale of map, which allows a user""s vehicle and a target object for a user""s destination to be displayed on an monitor, on the basis of a positional relationship between the user""s vehicle and the target object, whereby the user can be provided with a map information having the appropriate reduced scale and also an appropriate area in order to guide the user""s vehicle to the target object.
According to the invention, the above mentioned object is accomplished by a map information providing apparatus comprising:
a detecting unit configured to detect a position of a user""s vehicle;
a memory unit configured to store information including a map information therein;
a control unit connected to the detecting unit and communicated with the memory unit thereby to select the map information in the circumferences of the position of the user""s vehicle detected by the detecting unit; and
an onboard display unit connected to the control unit and configured to display the map information selected by the control unit; wherein
the map information includes information about target objects forming landmarks on a route for a user""s destination; and
the control unit comprises:
a searching part configured to search a target object for the moment with reference to the information stored in the memory unit, on the basis of the position of the user""s vehicle and information about the user""s destination inputted by a user;
a positional relationship analyzing part connected to the searching part and configured to analyze a positional relationship between the target object searched by the searching part and the user""s vehicle;
a reduced scale calculating part connected to the positional relationship analyzing part and configured to calculate a reduced scale of the map information to be displayed on the onboard display unit, on the basis of the positional relationship analyzed by the positional relationship analyzing part and a display format of the onboard display unit; and
a map information acquiring part connected with both of the reduced scale calculating part and the onboard display unit and configured to acquire the map information with the reduced scale calculated by the reduced scale calculating part, from the memory unit and further transmit the map information to the onboard display unit.
From another aspect of the present invention, there is provided a map information providing method for selecting a map information on the circumstances of a position of a user""s vehicle in response to a map information demanding order received from a terminal on the user""s vehicle, thereby to display the selected map information on an onboard display unit, the method comprising:
storing a map information including target objects forming landmarks on a route for a destination in advance;
searching a target object for the moment out of the target objects with reference to the map information on the basis of the position of the user""s vehicle and information about the destination inputted by a user;
analyzing a positional relationship between the searched target object and the user""s vehicle;
calculating a reduced scale of the map information to be displayed on the onboard display unit, on the basis of the analyzed positional relationship and a display format of the onboard display unit; and
selecting the map information in accordance with the calculated reduced scale and further transmitting the readout map information to the user""s vehicle.